Increased global datacom bandwidth demands have pushed internet transmission system providers to improve aggregate data rates through increased modulation speeds and multi-level signaling. The fidelity of the transmission link may be improved through real time processing of the received optical signal using digital signal processing techniques. Digital signal processing may allow for more of the receiver functions to operate in the digital domain. These include electronic dispersion compensation, error correction, signal conversion, out-of-band rejection, and filtering among other applications. The primary enabler for digital signal processing applications in this context are analog-to-digital converters (ADC).
In particular, high-speed ADCs may enable not only the real-time observation and processing of high-speed optical communications, but also storage of the signal for off-line processing. Such ADCs may also find applications in advanced radar, spread spectrum communications, radio astronomy, and signal transmission for remote antenna systems.
The demands of these systems call for high-bandwidth (>40 GHz), high-resolution ADCs which cannot be met by current electronic analog-to-digital converters (eADC). Although time interleaving could potentially relieve bandwidth demands, the jitter associated with electronic sampling limits the resolution of such configurations.